Pressure decline caused by the extraction of oil from deep sedimentary layers depends on the pore modulus K pp , a poroelastic parameter that characterizes the effect of pressure change on pore volume under constant mean stress. Measurement of K pp is difficult, however, as it requires calibration to account for fluid compressibility and compliance of the testing system. Nevertheless, knowing the easily measurable drained pore modulus K p and adopting an assumption on the unjacketed pore modulus K s , it is possible to determine K pp because these pore moduli are related. Previous work on indirectly estimating K s claimed that K s is strongly dependent on Terzaghi effective pressure P and therefore not a constant; also, K s might be different from K s , the solid bulk modulus of the major mineral constituent. We overcome the limitations of the indirect approach by directly measuring K s . The experiments reveal that K s is indeed a constant and that for an ideal porous rock, the assumption of K s = K s holds. Furthermore, a constant K s implies that K p and K pp are functions of Terzaghi effective pressure only. These results provide a framework to accurately determine the Skempton coefficient B.
|Original language||English (US)|
|Journal||Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences|
|State||Published - Nov 1 2018|
Bibliographical noteFunding Information:
Data accessibility. The experimental data in this paper have been uploaded as an electronic supplementary material. Authors’ contributions. A.T., E.D. and J.L. designed the research, wrote the manuscript and discussed the results. A.T. performed the experiments and analysed the data. Competing interests. The authors declare that they have no competing interests. Funding. Partial support for this research was provided by the MSES/Kersten Chair. Acknowledgements. Mr Mugurel Turos assisted in the development of the experimental set-up. Dr Siavash Ghabezloo and three anonymous referees provided salient comments and suggestions.
© 2018 The Author(s) Published by the Royal Society. All rights reserved.
- Effective pressure dependency
- Ideal porous solid
- Non-connected pore space
- Unjacketed pore modulus